Tag: bitx40

I was playing with my bitx build yesterday. Specifically, I tried to add CW to the rig. Original bitx20 is a SSB rig. I my mod was inspired from PY2OHH bitx40. I wired up a 10mhz crystal oscillator as shown below.

The idea is to inject 10mhz ( approximately) at the beginning of transmitter IF amplifier. This will in turn produce 14 mhz sine wave at the output. The receiver part is unmodified. See the diagram below. Connect the point marked X to the point x .

Bitx 20 modified for cw

Adjust the 10Mhz oscillator to around 700khz above the BFO frequency. I added a small inductor (10 micro henry) in series with the crystal to adjust the frequency near BFO,.It is not shown on the figure above.